The state said it recovered evidence of the emerald ash borer beetle from a tree in Concord's south end. Steps are now being taken to find out the scope of the infestation and slow its spread.

Late last month, heavy woodpecker activity around an ash tree on Hammond Street in Concord led neighbors to call in an expert who found larvae from the emerald ash borer beetle, an invasive insect from Asia that can kill most species of ash in just a few years.

"While they're feeding, they create these S-shaped galleries under the bark and essentially girdle the tree from the inside, so that's why death is pretty rapid," said Mark Michaelis of the U.S. Department of Agriculture.

The emerald ash borer first turned up in Michigan 10 years ago and has been working its way east. Entomologists said that based on the infested tree, the beetle was likely in New Hampshire well before the state implemented a firewood import ban in 2011.

"We can tell that this one is probably 3 or 4 years old at a minimum, and then there's some other trees that look to be three years infested, and then we think we may even have a tree or two across the river that are a couple years infested," said entomologist Kyle Lombard.

While the state conducts a survey in Concord and surrounding towns to determine the scope of the infestation, an immediate quarantine is in place for Merrimack County to limit the human-assisted spread of the beetle.

"(The) cost of doing business will go up. At the same time, that cost has to be kind of directed toward the landowners, so the landowners for that Ash component isn't going to be as high as it is now. Some of your best markets for Ash aren't in this county," said Jeff Eimes, owner of Fort Mountain Companies.

Among other things, that means hardwood firewood of any kind cannot leave the county without government approval -- a big change for loggers and landowners.

Invasive species are everywhere

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Invasive species are a significant threat in the United States. Native species, native habitats, commercial agriculture even recreation are at risk. The following reviews some of the better known invaders.

"There are certain ways they will be able to ship their products," said Brad Simpkins of the Division of Forest and Lands. "It's not an absolute ban. They can get compliance agreements. They just have to treat their products or mitigate their products."

Bug experts said that without efforts to stop the beetle, it could decimate New Hampshire's ash population in less than a decade.